The public switched telephone network (PSTN) has evolved into an efficient real-time, multimedia communication session tool, wherein users can pick up any one of nearly one billion telephones and dial any one of nearly one billion endpoints. Several developments have enabled this automated network, such as numbering plans, distributed electronic switching and routing, and networked signaling systems.
Similar to the manner in which the PSTN is based on a hierarchy, the Internet is based on an Internet protocol (IP). IP messages, or multimedia packets, are routed or forwarded from a source of a multimedia flow to a destination of the multimedia flow. Each multimedia packet comprises an IP address, which, in Internet protocol version 4 (IPv4), for example, has 32 bits. Each IP address also has a certain number of bits dedicated to a network portion and a certain number of bits dedicated to a host portion. It should be noted that the term “multimedia” utilized herein is intended to comprise one or more of the following: voice, data, text, graphics, animation, and/or discrete media.
More specifically, multimedia packets comprise a header portion and an IP packet data portion. The header portion of the multimedia packet, at a minimum, comprises at least a source portion and a destination portion, wherein the source portion identifies a source address from which the packet originated, and the destination portion identifies a destination address to which the packet is addressed. It should be noted that additional portions of the header portion may be provided, in addition to the source portion and the destination portion such as, but not limited to, a real-time packet header or a real-time control packet header.
The IP packet data portion of the multimedia packet comprises the remaining portion of the multimedia packet, which comprises data that is being transmitted to a destination device located at the destination address.
As the multimedia packet is received by different devices on a path taken by the multimedia packet to the destination device, it is common for the source and/or destination portions of the multimedia packet to change properties, thereby reflecting a most recent source and destination.
Therefore, it is difficult to determine the original source of a multimedia packet. Having knowledge of the original source of a multimedia packet allows the destination device to accept or decline acceptance of the multimedia packet based upon the original source of the multimedia packet.
The acceptance or denial of multimedia packets based upon the original source is a characteristic of devices such as, but not limited to, firewalls. Unfortunately, since the header portion of the multimedia packet is changed by devices within the transmission path to the destination device, the original source of the multimedia packet is not known. Since the original source is not known, the destination device is not capable of accurately declining receipt of multimedia packets from a predefined source.